Hydrostatic tail fuse



Sept. 22, 1953 R. 1 .v GRAUMANN 2,652,777

1 HYDROSTATIC TAIL FUSE:

Filed July 15, 1941` lNvENToR @fmandL-Gmz/ma1m/ A ORNEY Patented Sept. 22, 1953 "UNI TED )S TAT ES PLATE N .T

jOFFICE -6 Claims.

:This zinvention :relates 1 ato '..a tail fuse f. for an .aircraft .bomb, particularly l,to ...tail :'fuse .for an aircraft depth bomb of @the .type 'having -La lockedearrning.mechanism-which isreleased only afterthe bomb .upon :which itis mounted has :tallenrga'` certain `distance through theair and more partcularlvto the type of fuse .in :Which thegdetonationfofl the bomb ywill be initiated` by kthe fuseronlyafter the bombhaspenetratedthe 'watenarzpredetermined distance.

=:It.-is anobject of this invention to provide ia Vbomb .fuse :having a .hydrostatic pressure -sensitive'member the .movement of which, in respensel to predetermined. hydrostatic: pressure, .initiates the :detonationof said bomb, the Aar- 'rangementfof Aparts l ybeing f suchthat .the hydrostaticgspressure sensitive member in order to ini tiate detonationemustmover-outwardly .or away .fromr the normalcdirecticnof travel of the freely falling. bomb.

.It isa further objectzof this invention topro- .vide ia :bomb fuse, -the transmission ignition trains of which-.are .normally yieldably heldV out of alignment in the unarmed vpositionuntil-the -high inertia forces producedby thedeceleration of;the bombin traveling throughthewater have been .apprecably reduced.

It isa still furtherobjeet lof this invention to provide a tail fuse for an aircraftfdepth bomb vthe'transmission:trains of which .are arranged `anadjustment,for changing. thedepth at `which Vthe:detonatiori oltherbomb willbe initiated.

I,It;is;1alsoffan object o'f thisinvention tao-aprovide a lock for a hydrostatic tail fuse which'will prevent the detonatcrvcarrier memberfrom being :moved by the lzhydrcstat to bring the transwmission f ignition trains -into alignment :thereby :armingithe fuse: untilthe bomb hasfallen-freely a ,'lpredetermined.distance, The'detonation of the bombcannotthereforebe initiated asa resultoi a -severe impact, fshock, cr Vas a result `of the nforces ofracceleratien which :acts upon thedetonator` carrier .during the .acceleration of vthe lairr`:craft :upon which -it is mounted .or asra iresult Kof the-:facceleration-:of .the freelysfalling bomb..

4\When .f-aircraft `depth v-bombs :are ibeing r loaded inf.thefbombingoracks of an :aircraft they. may be @subjected to :severe :shocks `oroccasional jars,

1which could .cause :1a premature adetonation of @the :bomb furthermore, the lmembers l.wl'lich f.

.22 aarezmovable Within vthe bodyfo the. fuse to initiate f. the ignition: Would,- when mounted. iupon. an aircraft, fbesubject'to thefsame. yforce off acceleration "eWhichY-fa'cts .upon .the aircraft Aduring .These forces nof acceleration when act- .inguponithese movablefmernbers `could cause f a .premature detonationof the bomb .unlessfsorne precautionary.measuresiareprovided in the design of e' a bomb`- which-f-absolutely precludes vvany premature.. detonation l causedv by Lthe movement of z these .membersneitheri asf-a'. result. of. an accidental impactnnas afresultof thefforces 0facvceleration actngthereon.

.In this, invention I;- have vgprovivzled ifa fuse .designed :t-ogpreclude;` premature `detonation'loy providing a locking means for the movablerdetonator-.carrieritinemben .Thisfloekin'g means retains thesdetonatorcarrier invaxpositioniwherein the transmission4 i'gnitionf trains` aretbroken and .held-.out ofvalignmentffso thatfevenvy-though `a :severedmpacLncould causethe-.ring oinv to.y free itself from its :securing means and impinge .against the Apercussion r cap f to :initiate -the 4ignition, .the;ignition-would not.v loe-.propagated to. the boosterecharge'tol-detonate the .bomb because the'transmissionfignition trainflea'ding from the detonator islnotinl ignition conductive relation- -.ship-withithebooster.charge of the fuse.

Ingorder `.to be most eifective depth bombs .sh-Ould be ,exploded at .predetermined -depth fbelow.thesurface ofthe water. :Asis Wellfknown, .the explosive forces `of fra depth charge -set olf :below thesurf-ace--of the water; decreases las the .distanceA from'the,chargeiincreasea. andi the dis- .tance.,ati-whichethesei forceslare effective vagainst .a .-targetedetermines the danger zone of -v the. det- .onating-charge. .Theuse should preferablybe :seti-so asta-initiate .detonationof the bcmbat a distance below the surface of the water equal .tovathe radius off'therdangeiuzone,because the ,leffectve. area'of a.target -would be `increased and the accuracy.- requiredfinrdropping a bomb would vbe f acccrdinglyfdiminished. `llaturallyl the danger zones arez-di-erent for v:different types of Lvessels. 11n-.order forsa bomb Vto be effective `against fa heavily/armor plated vessel it :should sexplode. closer-to .the :'hullithan. is necessary when used against a vessel having lighter armory plat- .;ing. .lt isimportant,:thereforeftohave an easily and readily accessible adjusting means-thesetv.tirigs .of which `'will :accurately determine the depth at which thebombawillfbeexploded. lur- .thermore, when the .bomb vvis sused .againstsubmarines, the bomb should be set to .explode at v.orinearvtheisubmergenl-depth of.the vessel.

In the prior art fuses, the detonation of depth bombs is initiated as a result of both the hydrodynamic and hydrostatic forces acting upon the bomb. Consequently, no accurate means of adjusting the depth at which detonation takes place can be provided since the hydrodynamic forces decrease as the penetration of the bomb in the water increases; This type of prior art fuse is also more likely to be set off upon imp-act, a result which is undesirable and in fact absolutely impossible with the depth bomb fuse of this invention.

In order to accomplish the foregoing objects I have provided a tail fuse which carries a tetryl booster charge and associated tetryl leads which connect the booster charge with a detonator and percussion primer, the major portions of the tetryl leads are formed in the body of the fuse while the remaining portions thereof are formed in a detonator carrier member. This carrier member is movable in the body of the fuse against the action of a spring or other suitable yieldable means. The spring or other suitable yieldable means normally retains the carrier in a position in which the tetryl leads are out of alignment. In order to bring these leads into alignment to arm the fuse a suitable hydrostat such as a hydrostatic piston, is connected to the detonator carrier member so as to move the carrier in the body of the fuse in a direction away from the booster charge and opposite to the normal direction of fall of the bomb. This hydrostatic piston will therefore arm the fuse when the forces transmitted by it are greater than the force of the spring and theI inertia forces acting upon the bomb.

A ring pin is also positioned within the detonator carrier member so as to be spaced from the percussion cap. This ring pin is released to impinge against the primer only after the detonator carrier member is moved a distance equivalent to the distance required to bring the transmission ignition trains into alignment. The movement of the carrier member also compresses a ring pin spring which forces the piston firing pin against the percussion cap when the latter v is released from the carrier member.

A locking means is provided which prevents movement of the detonator carrier member in the body of the fuse until the bomb has fallen freely through the air a required predetermined distance. Thus, even though the bomb were to accidentally fall overboard while being loaded on shipboard, it would not explode even though it were to reach a depth equivalent to the depth setting of the fuse. It should therefore be apparent that I have devised an extremely safe and yet sensitive fuse for an aircraft depth charge.

Additional features and other objects of this invention will become apparent when considered in reference to the construction, combination and arrangement of parts hereinafter described and illustrated in the drawings, in which:

Fig. 1 is a cross-sectional elevational view of a bomb constructed in accordance with my invention, the section being taken on lines I-l of Fig. 2,

Fig. 2 is a cross-sectional view taken on lines 2--2 of Fig. 1l

Fig. 3 is a detail view showing the features of the depth adjusting collar, and

Fig. 4 is a cross-sectional view taken on lines 4 4 of Fig. 1.

Referring now to the details of the QQnStluG'- tion illustrated in Fig. l, the main portion of the fuse, indicated generally at Iii, is provided with an enlarged annular portion il, and a reduced neck portion I2. The diameter of the neck portion I2 is further reduced at an end which is `threaded, as at I3, to receive a cylindrical cup shaped member I4 containing the tetryl booster charge I5. The body portion of the fuse is also provided with a longitudinal concentric bore I6 within which the detonator carrier member I1 is adapted to be slidably supported. The end. of the bore adjacent the tetryl booster charge is provided with a suitable removable plug I8 which is provided to seal this end of the bore from the tetryl booster charge. Transmission ignition trains I5 are formed in the body portion of the fuse and are arranged so that one end of each is in ignition conductive relationship with the tetryl booster charge, while the other end of the trains communicates with the bore I6. I

The detonator charge 2l! is supported in a longitudinal concentric bore 2i formed in the detonator carrier member I1 and held in place by a suitable removable plug 22. The transmission ignition trains 24 are formed in the detonator carrier member so that one end of each is in ignition conductive relationship with the detonator 20. These trains 2G are formed in the body of the carrier so as to extend radially from the detonator 23 to the outer cylindrical surface of the carrier member, so that when the carrier member is moved longitudinally Within the bore the transmission ignition trains I9 and 24'are brought into alignment. The spring 25 is positioned around the detonator carrier member so as to lie between the depth adjusting collar 26 and the flange plug 21 which is threadably secured in the end of the detonator carrier member I1. Thus the spring 25 yieldably holds the detonator carrier member I1 in a position at the limit of its forward movement, wherein the ends of the transmission ignition trains IS remain out of alignment with the ends of the transmission ignition trains 24;

A percussion primer cap 28 is also securely held in the carrier member at the end of the bore 2l opposite the detonating charge 2G by a suitable plug 29. One end of the carrier member I1 has an annular ange portion extending therefrom forming a sleeve 32 into which a firing pin 3| is secured by means of a plurality of balls 33. The firing pin is retained in the position illustrated in Fig. 1 spaced from the percussion primer by means of these balls 33 which are re cessed in the body portion of the firing pin and extend outwardly therefrom into the openings 34 which are drilled or otherwise suitably formed in the sleeve portion 32 of the movable carrier member I1.

A cylindrical cap member 35 is threadably secured to the body portion i@ of the fuse as at 36. This cylindrical cap member has an annular ange portion 31 which extends inwardly from the base 38 to form a cylindrical cavity or socket 39 into which an end of the ring pin spring 4I) is placed. The other end of this spring surrounds the neck portion 23 of the firing pin body 3l and abuts against the shoulder 42 formed thereon. The inner diameter cf the flange portion 31 is equal to or slightly greater than the outer diameter of the detonator carrier member and forms a guide therefor. The end of this annular flange portion 31 extends inwardly from the base a sufficient distance so as to cover the drilled openings 34 formed in the carrier member I1.

v ihei inner; sixrftaceof rithistalsoggirovided 'wmianeannularfgmove o .adapted toireceivetthe rballs fand-.releasetheringzpin Irfromitsgengagementf-With lfthessleeve tportion 53 Blfof fthe fear.- ir-ieri'member I11.

hydrostatic pressure. `suitable Sylphon bellows 34:5 Ii-is secured this '-'fhydrostatic piston oand to the fboy 4-"me1i`1ber of 'tla'e J"fuse Sitable :openings JCB V^are a drilled into fthe f'bodyf member #soiesitofcommuicate with'thewidsspaceiformed by'thelhydrostatic'fpiston5M `and thefylphonil'. 'Openings 41 :are 1 also idrille'd into the''body por- Ltionfofit'heifuse `=so rasato `/receivefthe detentsi-4`8, eeacho'fLWhieheengages"aireeess feffiormed `.in vtthfe at-:arrier fmember W1'fwhen-fthei-ldetents lare in- ;seted into thesef'openings i141 afgamstitl-iemaetion fof fthe Lspring fmeans :.5 I. "These fietents 518 `sel'curl'y'llold `the f carricrmeniber in tithe fposition .lshown inFig.

A cover 505ispositicne'deabout'-thelcapmember l:and thebodyfporticn of theffuse'sofasstoretain the detents -=48 Ain their slot'engaging -'position. "'lheopposite end 'of this `capi-is provided *with 17Va ihub"portion "56 which -is internally threaded -to i'receive'-thethreaded-endAof the-shaft 52.. This *shaft *is rotatably Lsupported fin'fthe "bearing 513 A sun gear 55 is integrally *formed about the hub'portionWfG-of the protective-"housingf54. The taillendf'' the'I housingi 1' yisy `securedfto f the main f'housing" by'means onscrevc's*513andy extendsrearported. -lAn air screw '"6 I `is pinned lto the Ashaft 180 rattan "end ithereo. vrThe other kend `of "the shaft IH! rhas"secured"thereto a yoke Limemberili! 'the `forked ends V'of 'Wh-ichsare'securedtottheblock "B3 "which Yis preferably ""formed "of Bakelite vor other suitableplasticfmaterial Aand which is 'ro- 'tatable l'.fftbout *the *shaft l"52. "The planet gears 'W5 arid A"SI5 vxare"rotatablytfsuppcrted iin 'this block member fi3 "to *form Mthe differential 64, Gear *member L155 meshes .with the sun gear l*EEW/h'ile drivesthe'shaft""5'2. Thelbearin-ghubhas an annular shoulder 'extending along "thefshaft lill "so "that a v.suitable "arming Wire 'may :be 'inserted h"throulfhthe "drilled -openings "58 "formed inv4 the i'iange'an'd thedrille'dopenings *69i`formedin said rshaft "membeia V The .protectingsleeve.member 54 has a suitable vent""`fonned therein which connects with the void. space ,formed about thev,.cover50. and= allows the water into which the bomb has penetrated to reach-the drilled vopenings '46 formed in the body smember II) of the `fuse. A plurality :of

V44:radially:extending .tapped openings 1 I are drilled .ithI:oughttheprotectingcsleevesardl the bo'dyfmemlber .ILD ofitheiuseso .thatithethreadedupins"12 v`which :a are-inserted Ytherein will engage f slots 13 "Whiclrareiormedin the depth-adjustingfcollarZ6. lThe operation `of Vthe depth fadjustingfcollar i is as `L`1oll'ows:

"Ihe`| lock-screw -1`4- extendsfthrough -ltheiilled fopening-s '1I formed intheiproteeting =sleeveand the body portion of the fuse to engage the pin 15 formed in the collar. When the collar is held in its locked position the spring member is under maximum tension. In order to change the depth setting for the fuse the lock screw 14 is removed from its engagement with the depth adjusting collar. The depth adjusting collar 26 is thenheld inijplacebyeanyonestzofsthezthreesre maining threaded pinsic12,aeachofswhichengages u.a isiot 'inf :diierenttaxial extent :formed in the .depthzaadjustingx liars as :Lillustratedt in 'Eig. :3.

',The rqperationzofzimy :.rhomb .is :as iollows the:,bombztomzhichithisxfuse:isfadapted to be attached is loaded on theibomb racksan aircraft, the cover securely holds thegdetents iiintothezpositio-n aofilocking engagement with "10 @the marrierrmember. .A;suitab1e.;arming zwire Y1li tis fadapted :to be inserted :through @the :drilled :openings vmirand'sllgformed.inithehubf.ofgthef tail hon-sing 'aand ,the :air screw .i-shaft.. respectively, .zin mrdertoiockf; thairiscrewfshaft ,tof the housing `1'5 :51. Whemtheibombiis vreleasedfrom:itscarrier irack ,thisgarmingslwire ziseremoved fromitsgposi- Y tien@ ofldeking e agement withigtheishaft :.60 that the I-ffwvilkrotate egthisshaft in; its Mbearin isseausing hecplanetarygearszto-rotate y20 about-:theraxisvinfstherfshait 52, rotating this shaft :15.25 @the .detents 4.8fto flyqradially ,outwardlyfof ythe iboldysmemberfof fuse iso :fas to `dsengagethe a detonator-'carrier member I1. .The .bomb :fuse is now in the unlocked unarmed position fandwill r`remain/.in this,position.unti1 the-.bomb has 'spene- 30 trated the :water :to a depth :equivalent to -the fdepth "setting of -the -.depth Aadjusting .'collar. When the bombhaszattained thisdepth'th'efwater 'which has :entered the protecting :housing through -the `,vent 1.0 4.andfinto Athe void space formed-.by .the Sylphon: 4 5 fand hydrostatid piston M vwill cause;`y the piston to move .1 the *'.detonator carriermemben I1:;so;that the tetryltleadsy or; ignition k.transmission :trains I9. :and .24'f are brought rfinto alignment.

#When the fcarrieremember i I 1 hasv .moved this '..distanoe theeopening-srd' formed :infthexsleeve 13.2 will V.be.radially-aligned with thefannular notch :43sogthattherballs Willbe freed .Ofitheir lock- .f.ingeiengagement-awithfthe ...body-.of the.` firing pin 3 I.. The ringjpin will? thus be'released yand the tispringed Ewllsforce ittofimpinge against the per- ..cussionfprimergcap 28 to initiate'the detonation `of ,the'bombi It :should f'benoted thatY .in nthewposition shown in Fig. .11irrespectiveof .@anyglocking` of v the vdetonatorscarrier:memberl-by the detents 4l8,ethe.carrier member @could not .-be 4moved',y to l .thegarmed position .upon Limpaet of :the ibomb, :because: the inertia forcesswhich .would :act: upon :this carrier m emberetending z'tox'move;v it .upon impact. are in la .directionaoppositeifrom `;1:l 1e=-'direction in which @this y-detonator tearrier member =must -move in ,in-tolal-ignmen-t to .release fthe ringgpin. Eurthermore, .the @openings 4G-formed.; in the tbody .portion*oflthelfusetandtheyent 1U-.formed ,in :the

,prcdzecting sleeve.-areisoearrangedtthat ithe inertia forces-.of Lthe :bombicausedfby .t-herrelative'movement of: the bomb throughthe water Vcannotfact f,upontheihydrostatic piston to-'fc-ause agspremature detonation, .or.-in-.oth'er, words, vto-.cause therdetonation; toy bednitiatedbyi, the hydrodynamic? forces I .present when4 the ibombff-isgpenetratingrgthe:Water and before the bomb has attained a depth at which the hydrostatic forces alone would actuate the hydrostatic piston to initiate the detonation of this bomb.

Other modications and changes in the number and arrangement of the parts may be made by those skilled in the art Without departing from movable within the body member away from said charge and in a direction opposite to the direction of travel of the bomb to which the fuse is adapted to be attached, means responsive to the movement of said carrier for initiatingthe ignition of said booster charge, and hydrostatic pressure means for moving said carrier, last said means comprising a bellows surrounding said carrier, one end of said bellows being connected to said body member and the other end to said carrier, and means for admitting water to the interior of said bellows whereby detonation of the bomb will not be effected by impact if the bomb should strike an object but only after it has passed through a predetermined depth of water.

2. In an aircraft bomb fuze the combination including a. movable ignition transmission train, a primer associated therewith, a stationary ignition transmission train, resilient means for retaining said movable ignition transmission train out of alignment with said stationary ignition transmission train, locking means for retaining said movable ignition transmission train in said position out of alignment with said stationary ignition transmission train, means responsive to the movement of the bomb through the air for releasing said locking means, hydrostatic pressure responsive means for moving said primer and movable ignition transmission train against the action 4of said resilient means to bring the same into alignment with said stationary ignition transmission train whereby the fuze will be armed only after the bomb to which it is adapted to be attached has fallen freely through the air a distance sufficient to release said locking means and penetrated the water to a depth at Which the hydrostatic pressure acting upon said hydrostatic pressure responsive means is greater than the resistance offered by said resilient means.

3. A tail fuse for an aircraft depth bomb comprising an elongated body member having an opening through a side Wall thereof, said member being adapted to be inserted in the rear end of said bomb with the longitudinal axisthereof parallel to the longitudinal axis of the bomb, a detonator carrier movably supported Within said body member for movement along the longitudinal axis of said body member, said carrier including a recessed portion, yieldable means retaining said carrier in an unarmed position from which it is movable a predetermined distance to an armed position in a direction opposite to the normal direction of fall of said bomb, means responsive to the movement of said carrier through the predetermined distance against said yieldable means for initiating the detonation of said bomb, means locking said carrier member to said body comprising a pin resiliently held in the side wall opening of said body member and seated in the recess provided in said carrier so as to prevent said carrier member from being moved through said predetermined distance relative to said carrier, and means responsive to the movement of the bomb through the air for releasing said locking means after the bomb has traveled a predetermined distance.

4. In a depth bomb fuse, the combination comprising a tubular body member, a carrier member slidable within said body member, a primer and cooperating iiring pin supported by said carrier member, a coil spring one end of which engages said carrier member to bias it in one direction to a first position, means for selectively fixing the position of the other end of said spring to vary the biasing action thereof, a hydrostatic pressure actuated device for moving said carrier in the opposite direction, and means actuated when said carrier member has moved a predetermined distance in said opposite direction to cause said firing pin to detonate said primer.

5. The combination in claim 4 wherein said means for selectively positioning the other end of said spring comprises a slidable collar engaging said other spring end and provided With a plurality of spaced slots, each said slot being of a different length, and a removable pin for each slot, each said pin extending through said body member into its associated slot.

6. In a depth bomb fuse, the combination comprising a tubular body member, a carrier member slidable within said body member, a primer and cooperating iiring pin supported by said carrier member, a coil spring one end of which engages said carrier member to bias it in one direction to a first position, an adjustable collar engaging the opposite end of said spring, said collar being provided with a plurality of spaced and axially extending slots arranged such that successive slots progressively increase in length from a transverse reference base line, a pin for each slot, each said pin being threaded through the Wall of said body member and extending into its associated collar slot whereby compression of said spring may be progressively decreased by unthreading said pins in succession from said collar slots, a hydrostatic pressure actuated device for moving said carrier in an opposite direction, and means actuated when said carrier member has -moved a predetermined distance in said opposite direction to cause said firing pin to detonate said primer.

RAYMOND L. GRAUMANN.

References Cited in the iile of this patent UNITED STATES PATENTS Number 

